The present invention relates generally to methods for mitigating plant stress.
Biological stress has been defined as xe2x80x9cany change in environmental conditions that might reduce or adversely change a plant""s growth or developmentxe2x80x9d (J. Levitt, 1972, Responses of Plants to Environment Stresses, Academic Press, Inc., New York and London). Adverse environmental conditions such as water deprivation, pathogen attack, salinity and unfavorable growing temperatures are common stresses that limit agriculture yields. For example, it has been estimated that the world rice production would decrease 50% if the world mean temperature dropped by only 1.0xc2x0 C. (F. B. Salisbury and C. W. Ross, Stress Physiology in Plant Physiology, 1985, published by Wadsworth Inc.). Moreover, a comparison of average and record yields of eight major crops showed that average yields were only one-third to one-seventh of record yields (Boyer, Science, 1982, 218:443-448). More than 70% of the loss of potential yields was attributed to unfavorable growing conditions caused by factors such as weeds, disease, soils, climate, etc. (Id.). Unlike animals, which are able to move into less stressful environments, plants rely on chemical defenses to respond to stress. When plants are exposed to unfavorable high growing temperatures, normal protein synthesis is reduced and rapid synthesis of heat shock proteins commences (J. L. Key and Y. M. Chem 1981, Proc. National Academy of Science 78:3526-3530). Similarly, low temperature acclimation in plants is associated with the synthesis of specific extremely hydrophilic proteins which act as cryoprotectants, much like anti-freeze (J. G. Boothe et al., 1997, Plant Physiol 113:367-376). In response to invasion of plant tissues by pathogens such as insects or fungi, stress induced lignin deposition occurs to seal off the site of wounding (R. A. Dixon and N. L. Pawa, 1995, Plant Cell, 7:1085-1097). Many plants respond to drought and salinity stress by accumulating high levels of protein, which is believed to protect plant tissues from osmotic stress (G. R. Stervant, et al., 1976, Plant 120, 279-289).
Thus, it can be seen that plants have developed specific patterns of stress mediated metabolism in response to various environmental and biological challenges. Efforts to mitigate the effects of plant stress have included complex methodologies that are both time consuming and expensive. For example, in order to inhibit pathogenic conditions of plants, recombinant DNA technology has been used to incorporate genes into the plant genome that encode polypeptide and complementary oligonucleotide inhibitors. In order to mitigate the effects of different forms of stress, it is usually necessary to incorporate other genes into the plant""s genome that will be effective in eliminating the particular stress involved. More over, prior to the present invention, most methods to mitigate stresses have been directed at specific stresses. For example, a method to protect a plant from a specific fungal infection would not be expected to protect against all fungal diseases. It would certainly not be expected to protect plants from heat or cold stress. In contrast, the present invention provides a general method for protecting plants from diverse environmental and biological stresses. A simple, safe and cost-effective method to mitigate a wide variety of plant stress is needed. The present invention addresses this need.
The present invention relates to a plant stress mitigating compound and a composition. In one aspect of the invention, a plant stress mitigating compound including gamma aminobutyric acid is provided. In another aspect of the invention, the plant stress mitigating composition including gamma aminobutyric acid and glutamic acid is provided. The composition may further include a source of proteinaceous amino acids as well as a salt of calcium.
In yet another aspect of the invention, the plant stress mitigating composition including gamma aminobutyric acid and a source of proteinaceous amino acids is provided. In a further embodiment of the invention, a plant stress mitigating composition including glutamic acid and a source of proteinaceous amino acids is provided.
In a further aspect of the invention, the compound or compositions of the present invention may be combined with a pesticide to form a synergistic composition effective in increasing the level of control of plant pathogens.
The present invention also relates to a method of mitigating the effects of plant stress. The method of mitigating the effects of plant stress includes treating the plant with a compound including gamma aminobutyric acid.
In another embodiment of the invention, a method of mitigating the effects of plant stress including treating the plant with a composition that includes gamma aminobutyric acid and glutamic acid is provided. In other embodiments of the invention, the composition may further include a source of proteinaceous amino acids and a calcium salt.
In a further embodiment of the invention, a method of mitigating the effects of plant stress including detecting the presence of stress in a plant, and treating the plant with a compound or composition as described above is provided.
In yet a further embodiment of the invention, a method of preventing plant stress or mitigating the effects of plant stress including treating the plant with the compound or composition of the present invention prior to the occurrence of plant stress is provided. The method includes initially predicting when a stressful condition will arrive prior to treating the plant.
It is an object of the invention to provide a compound effective in mitigating plant stress including gamma aminobutyric acid.
It is a further object of the invention to provide a plant stress mitigating composition including gamma aminobutyric acid and glutamic acid and including, optionally, a source of proteinaceous amino acids and a calcium salt.
It is a further object of the invention to provide a method of mitigating the effects of plant stress including treating the plant with gamma aminobutyric acid, either alone or in combination with glutamic acid and either a source of proteinaceous amino acids, a salt of calcium, or a mixture thereof.
It is a further object of the invention to provide a method of mitigating the effects of plant stress including detecting the presence of stress in a plant, and treating the plant with gamma aminobutyric acid alone or in combination with glutamic acid and either a source of proteinaceous amino acids or a salt of calcium.
It is yet a further object of the invention to provide a method of preventing plant stress including treating the plant with gamma aminobutyric acid, gamma aminobutyric acid and a source of proteinaceous amino acids, or gamma aminobutyric acid, glutamic acid and a source of proteinaceous amino acids and, optionally, with a calcium salt prior to the occurrence of plant stress.